Greenness assessment of analytical methods for determination of cannabinoids in oils using NEMI, Analytical Eco-Scale, AGREE and GAPI

Abstract

The cannabis plant is being increasingly researched due to its numerous therapeutic properties leading to the need for analytical techniques to assess substances present in extracts of the cannabis plant in carrier oils, such as medium chain triglycerides (MCT) oil. Awareness of the environmental impact of activities related to analysis led to the development of greenness assessment metrics. This study aimed to assess the environmental impact of analytical techniques applied in the analysis of cannabinoids in oil using Green Analytical Chemistry metrics. The first phase of the study consisted of a systematic literature review to identify high performance liquid chromatography and ultra high performance liquid chromatographic methods of analysis for cannabinoids in oil. In the second phase, the identified methods were assessed using the National Environmental Method Index (NEMI), Analytical Eco-scale, Analytical Greenness Calculator (AGREE) and Green Analytical Procedure Index (GAPI). Out of 124 identified studies, 8 were considered for the comparative analysis. The identified analytical methods consisted of high performance liquid chromatography (HPLC) using high resolution MS (n = 1), DAD (n = 2), UV (n = 1), UV and MS (n = 2) and MS/MS (n = 2) as detectors. When the analytical methods were assessed using the Analytical Eco-Scale, 7 out of 8 methods achieved a score ranging between 50 and 73, categorising them as acceptable green methods of analysis. One method achieved a total score of 80, categorising the method as an excellent green analysis. The application of Green Analytical Chemistry and respective metrics during the development of analytical methods contributes towards a reduction in the environmental footprint which results from related activities.